1. Field of the Invention
The present invention pertains broadly to a device for collecting soil samples, and more particularly to such a device which is mechanized and mounted upon a vehicle for enabling a single operator to rapidly and accurately collect a series of individual test samples and place the collected samples in receptacles for subsequent analysis.
2. Description of the Prior Art
In the field of agricultural production, farmers are constantly challenged in an ever changing economy to seek ways to increase efficiency and profitability of production. One routine commonly employed to that end is the carrying out of a soil testing program to determine the proper rates of application of fertilizers and herbicides. In order to achieve more accurate fertilizer application, and thus better utilization, it is highly desirable to assess the soil fertility throughout a field. This requires intensive soil sampling, for example on a field grid basis, involving collection of many soil samples for separate laboratory analysis.
As will be readily apparent the success of such a program depends upon the proper and inexpensive collection of soil samples. The samples must consistently represent the true soil conditions of an area to be treated. For example, the samples must represent the true available nutrient status of an area to be fertilized, or other appropriate parameters for areas to be treated with herbicides, insecticides and the like. The majority of technological advances in this field has been in the development of nutrient and herbicide application equipment, and the technique of soil sampling has not kept pace. Many suppliers currently using computer-controlled fertilizer and herbicide applicators still collect soil samples by means of a hand operated hollow tube probe, with no depth indication. Consequently, the soil sampling is highly subjective and operator dependent. The benefits of sophisticated computer-controlled fertilizer and herbicide application cannot be fully utilized unless the precision and accuracy of soil sampling is improved.
As heretofore indicated soil sampling has in the past, and still largely is, done by manually inserting a hollow tube probe into the ground a certain distance, and then withdrawing the probe containing collected soil. The collected soil is then removed from the probe for subsequent analysis. As can be readily appreciated, this is a laborious and time consuming task not conducive to intensive soil sampling. Furthermore, due to resistance to penetration under certain soil conditions and obstructions such as rocks beneath the surface, the samples tend to be taken at different depths so as to produce inconsistent test results.
Various types of mechanical soil samplers have been proposed, a number of them incorporating hollow tube probes into mechanism supplying weight and power for causing the probe to penetrate hard soils. Examples of such devices are disclosed in U.S. Pat. Nos. 3,464,504, 4,284,150, 4,333,541, 4,685,339, and 4,828,047. Other mechanical samplers employ a rotatably driven auger shaft which bores into the soil and withdraws a sample into a receptacle. Such devices are disclosed, for example in U.S. Pat. Nos. 3,593,809, 4,482,021, 4,534,231 and 5,076,372.
These devices are of substantial size and complexity and are generally designed-to be operatively mounted upon a large vehicle such as a tractor or a heavy duty pickup truck. While the devices may eliminate the back breaking work of manual probing, each involves either the time consuming step of the operator frequently dismounting the vehicle for sample collection, or the services of two workers, one operating the vehicle and the other operating the soil collection device, to achieve greater speed in sample collecting. The rate of sample collection and efficient use of labor were apparently not of particular significance in the design of the devices. In addition, the prior art vehicle-mounted samplers are limited to use under weather and soil conditions which permit operation of the carrier vehicle, that is, the tractor or pickup truck in the field. The prior art devices thus do not entirely satisfy the requirements of present day agricultural practices for a soil sampling device which will make possible accurate and rapid collection of soil samples efficiently and inexpensively.